As shown in FIG. 5, a heat pump type hot water supplying apparatus is generally provided with a tank unit 52 including a hot water reservoir tank 51 and a heat pump unit 54 including a water heat exchanger 53. A water intake port 55 formed at the bottom of the hot water reservoir tank 51 and a hot water inlet 56 formed at the upper portion of the hot water reservoir tank 51 are connected to each other through a circulating path 57, on which a water circulating pump 58 and a heat exchanging path 59 are disposed. In this case, the water heat exchanger 53 constitutes the heat exchanging path 59, which is heated by a heat pump type heating source. Specifically, a boiling operation is performed such that the water circulating pump 58 is driven, water which has not been heated yet is boiled by the heat exchanging path 59, and then, the heated water is returned to the hot water inlet 56.
Here, the heat pump unit 54 includes a compressor, an expansion valve and an evaporator in addition to the above-described water heat exchanger 53, although not shown, wherein the water heat exchanger 53 is allowed to function as a condenser by driving the compressor.